PowerWorld Simulator 7.0 Patch addresses problems that were detected in the program after its release and introduces some new functionality. These modifications are listed here. The patch was last modified December 12, 2001. Minor Updates made to this patch are noted below along with a date and explanation. This patch was first introduced on December 11, 2000.

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File Input/Output

• (December 11, 2000) Reading in a PWB file for which Custom Filters have been defined was not working properly. This has been fixed. Note: if you experience this problem, your PWB file is actually fine, but you will need to download this patch in order to read in the file.
• (December 19, 2000) Several minor corrections to reading in VAR devices from GE PSLF format. These included switched shunt devices and multi-line section line parameters.
• (January 16, 2001) Using a script file to control a switched shunt was not working. This has been fixed.
• (January 16, 2001) Writing "database friendly" tables out from the contingency analysis tool created blank entries under some circumstances. This has been fixed.
• (January 16, 2001) Significant improvements to saving PWB and PWD files were made so that the time required to save PWB or PWD files has decreased substantially.
• (March 20, 2001) A minor error in writing the multi-section line records for PTI RAW files has been corrected.
• (March 28, 2001) A minor error bug existed if you renumbered the zone's in your case, and then saved the case as a PTI RAW file. This was corrected.
• (April 13, 2001) GE PSLF *.epc files which contained no interface records were not being read properly. This has been fixed.
• (April 25, 2001) Added the ability to write interface records out to an Excel Spreadsheet in the "NERC Book of Flowgates" format. Removed Read/Write abilities for the old NERC text file format.
• (April 25, 2001) Added the ability to read PTI Version 27 format.
• (July 2, 2001) Modified the writing of PTI contingency file format to truncate contingency labels down to 12 characters.
• (July 2, 2001) Corrected bug in writing column headers out when using the "Save As HTML" option in a case information display.
• (November 16, 2001) Corrected bug when writing out a PTI formatted case. If the case description had exactly 1 line of text it resulted in a bug.

Power Flow Solution

• (February 26, 2001) A bug in the handling of DC lines in the power flow was causing power flow convergence to be slow. This has been corrected.
• (June 21, 2001) Under rare circumstances, a bug in the coordination of moving tap changing transformers and phase-shifting transformers together could be encountered. This would slow power flow convergence. This has been corrected.

User Interface

• (December 19, 2000) Minor changes in toggling the "Monitor" field on lines, interfaces, and buses in the Limit Monitoring Settings Dialog.
• (December 19, 2000) When setting to a flat start, all generator MVAR outputs were begin set to zero. This has been changed so that only generators that are on Automatic Voltage Regulation (AVR) are set to 0 MVAR.
• (January 16, 2001) When the line/transformers case information display is open, switching between Run Mode and Edit Mode might cause a nuisance access violation. This has been fixed.
• (February 26, 2001) On the TLR/Generation Shift Factors dialog, users can now specify the transactor to be either a single bus, or the slack bus. Also, the Injection Group feature on this dialog was not working properly. The results for an injection group always reflected the results for transactor with the slack bus.
• (February 26, 2001) On the TLR/Generation Shift Factors dialog the option to include phase-shifters in the DC calculation was not working properly. This has been fixed.
• (March 28, 2001) The user is now allowed to delete substations which contain buses. The buses are then set to be in no substation.
• (April 20, 2001) The automatic highlighting of fields on the one-line diagram after they reach a limit was not working correctly. The field would change color to blue or red upon hitting a limit, but the color would not be changed back after the element was not limiting anymore. This has been fixed.
• (June 12, 2001) Modified monitoring of limits to allow the user to monitor the lower end of a transmission branch for overloads.
• (June 21, 2001) When scaling flowing arrows according to percentage, sometimes the arrows were scaled incorrectly and the direction of flows was sometimes reversed. This has been corrected.
• (November 16, 2001) Fixed bug with the display of voltage fields on a one-line. This resulting in a "shadowy" appearance if you were showing voltages in kV, and displaying a contour.

Fault Analysis

• (December 19, 2000) Correct a mistake in converting per-unit values in the Fault Analysis to amps. The per-unit values were calculated correctly, but the conversion to amps was missing a square root of 3.
• (December 19, 2000) Added ability to show amp values in the list displays in amps.
• (January 7, 2001) An error was corrected with the modeling of shunts during fault analysis.
• (December 12, 2001) There was a bug with fault calculations caused by the 30 degree phase shift of Wye-Delta connected transformers not being properly taken into account. This has been fixed.

Linear Analysis Techniques: PTDF, LODF, Available Transfer Capability (ATC)

• (January 3, 2001) An error was occurring when calculating LODF values after a new transmission line was created. This effected LODF calculations as well as ATC calculations.
• (January 7, 2001) An error was occurring when calculating ATC values if branches included in the contingency list were not set to be monitored. This has been corrected.
• (April 13, 2001) Added two new options on the ATC form for determining which Transfer Limitations to report. One limits the number of limitations for a particular element of the power system. The other limits the report to include limitations below a certain MW level.

One-line Diagram Editing

• (December 11, 2000) User may now display the drawing grid on the one-line diagram.
• (December 11, 2000) User is now able to modify the number of digits and digits to the right of the decimal point on several selected analogs at once.
• (January 7, 2001) When entering new transmission lines on the diagram, the default drawing values for color settings were not being properly used. This has been fixed.
• (March 20, 2001) Pre-defined borders for all of North America were added.